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Ionization Clock

(40″ x 35″, acrylic, brass, electrical parts)This piece uses out of date technology to measure the temporal progress towards obsolescence. I first showed this piece at the DorkbotThingamajigger event called People Doing Strange Things with Electricity in 2007.

This is a digital clock. My aim was to make one without any semiconductors, or at least without any microchips. All the counting is done with 1950s era neon gas discharge cold cathode trigger tubes. The display uses nixie tubes. When operational, there are descending patterns of light that change with the time.

I wanted to make a large panel using open plan construction so that the circuitry was really visible. It was intended that this panel be free standing because you can see right through it. It was a lot of work to construct.

Each column is a 1 of N counter. The cycles of the 60Hz mains input are divided first by 10 then by 6 to get a one second count. After that the piece divides by 10, 6, 10, 6, and 12, to get the seconds, minutes, and hours.

I rather blindly followed schematics for trigger tube ring counters. As a result the piece has never correctly functioned. It is on my list of projects to go back and fix this. The counters were unreliable and the driving of the nixie displays was also terrible. It would stop, or one stage would fail to trigger the next stage. Essentially I need to go and work out how to make a reliable ring counter using these tubes. It was very much as a response to this failure that I decided to make my 867-5309 piece. In that I managed to get a very reliable driving of the nixie tubes using an appropriate biasing arrangement. I will eventually use this on the clock too.